Wind/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Tim and Moby are standing outside on a windy day. Tim's hat blows off of his head. TIM: Ah! Tim reads from a typed letter. TIM: Dear Tim and Moby, Where does wind come from? From, Hope. A door in Moby’s chest slides open and reveals a fan, which he turns on. TIM: Well, that's one way to move air. And that's just what wind is, moving air. But there's no giant propeller pushing wind around the earth. Believe it or not, the wind is caused by the sun. An animation shows a spinning globe, with its axis visible, close to the sun. The screen splits to show images of a hot sunny day and a cold snowy day to the left of the globe. TIM: If you’ve seen our thing on seasons, you know that the tilt of the earth causes some places to be hot or cold at different times of the year, and other places to be either hot or cold all year round. The uneven heating of the earth's atmosphere is what gets the air moving! An animation shows part of the earth's surface directly under the sun. Arrows show warm air rising up from the surface of the earth. TIM: The sun heats up the earth's surface, warming the nearby atmosphere. Warm air is less dense than cool air, so it rises. An animation shows the direction of warm and cold air over water. TIM: That leaves some empty space, and cool air from nearby rushes in to fill it. The area of rising air is what weather reports call a low pressure system. MOBY: Beep. TIM: As the warm air rises, it cools off and eventually sinks back down. The system is like a big engine sucking in air from all around it. An animation shows that as warm air cools it returns to the earth's surface. TIM: What you end up with is a whole lot of moving air, and that's what we here at BrainPOP like to call, wind. An animation shows wind blowing tree branches, leaves, and small animals. MOBY: Beep. TIM: There are different types of wind that blow in different patterns. Prevailing winds blow all the time over a particular part of the world. An animation of a world map shows how prevailing winds stay in specific areas. TIM: They're constant because the equator always gets more direct sunlight than the poles. An image shows a rain forest. An animation shows the direction of the wind from the North and South Poles to the equator. TIM: Warmer air at the equator creates a huge low pressure area, which is filled by cooler air from the Poles. Their direction is affected by the earth's rotation. A split image shows wind moving in different directions in the Northern and Southern Hemispheres. TIM: Winds in the Northern Hemisphere are deflected to the right, and they turn to the left in the Southern Hemisphere. Jet streams are strong winds that blow about ten kilometers above ground. An animation shows winds high above land masses and bodies of water. TIM: They blow in circles, with one jet stream over each hemisphere, and they blow fast, up to two hundred kilometers per hour. An image shows the direction of the jet stream over each hemisphere. TIM: Jet streams can move big chunks of air and really affect weather. A jet stream moves quickly over Tim's head as he stands on a shore. TIM: Trade winds are mild, constant winds that blow toward the equator from the northeast or southeast. Where the trade winds meet, there's a calm area called the doldrums where there's hardly any wind at all. An image show the direction of the trade winds blowing above and below the equator. The image then shows a calm area over the equator. TIM: Local winds are particular to certain countries or areas. An animation shows wind moving a rooster weather vane. TIM: Geographic features like mountain ranges or bodies of water can drastically affect wind conditions and create localized winds like the Santa Ana winds in the North American Rockies and the Föhn in the European Alps. Images show snow-capped mountain ranges and a beach. TIM: Wind power can be harnessed to make electricity, which you can learn about in our energy sources movie. An animation shows wind turbines spinning in a field. Moby, standing with Tim outside, waves his arms up in the air. TIM: What are you doing? MOBY: Beep. TIM: What do you mean you're trying to break wind? You can't break wind. It's made of air. Moby puts his hand on his mouth and giggles in beeps. MOBY: Be-ee-ep. TIM: What? Category:BrainPOP Transcripts